ECS4660-28F_Management Guide-R03

C HAPTER 20 | Unicast Routing
Configuring the Open Shortest Path First Protocol (Version 2)
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to the common transit area, and specify a neighboring ABR at the other
endpoint connecting the common transit area to the backbone itself. (Note
that you cannot configure a virtual link that runs through a stub or NSSA.)
Figure 511: OSPF Virtual Link
Virtual links can also be used to create a redundant link between any area
and the backbone to help prevent partitioning, or to connect two existing
backbone areas into a common backbone.
Any area disconnected from the backbone must include the transit area ID
and the router ID for a virtual link neighbor that is adjacent to the
backbone.
This router supports up five virtual links.
CLI REFERENCES
◆ "router ospf" on page 1751
◆ "area virtual-link" on page 1765
COMMAND USAGE
◆ Use the Add page to create a virtual link, and then use the Configure
Detailed Settings page to set the protocol timers and authentication
settings for the link. The parameters to be configured on the Configure
Detailed Settings page are described under "Configuring
OSPF Interfaces" on page 811.
PARAMETERS
These parameters are displayed:
◆ Process ID – Process ID as configured in the Network Area
configuration screen (see page 790).
◆ Transit Area ID – Identifies the transit area for the virtual link. The
area ID must be in the form of an IPv4 address, or also as a four octet
unsigned integer ranging from 0-4294967295.
◆ Neighbor ID – Router ID of the virtual link neighbor. This specifies the
Area Border Router (ABR) at the other end of the virtual link. To create
a virtual link, it must be configured for an ABR at both ends of the link.
backbone
normal
area
isolated
area
ABR
ABR
virtual
link